Prefabricated semiconductor chip carrier

ABSTRACT

A semiconductor die carrier includes a plurality of electrically insulative side walls; a plurality of electrically conductive leads extending from at least one of the side walls, each of the leads being individually manufactured without use of a lead frame; a semiconductor die positioned such that the electrically conductive leads are disposed at one or more locations around the periphery of the die; and structure for providing electrical connection between the semiconductor die and corresponding ones of the electrically conductive leads. A method of manufacturing a semiconductor die carrier includes the steps of individually manufacturing a plurality of electrically conductive leads without use of a lead frame; extending a plurality of the electrically conductive leads from at least one of a plurality of electrically insulative side walls; positioning a semiconductor die such that the electrically conductive leads are disposed at one or more locations around the periphery of the die; and electrically connecting the semiconductor die to corresponding ones of the electrically conductive leads.

This application is a continuation of U.S. patent application Ser. No.08/208,586, filed on Mar. 11, 1994, now U.S. Pat. No. 6,339,191.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a prefabricated, peripherally-leaded,semiconductor chip or die carrier having a reduced size, and methods formaking and using the semiconductor die carrier. In a preferredembodiment, the semiconductor die carrier has horizontally andvertically spaced rows of multiple leads, with each lead being assembledinto the semiconductor die carrier as an individually manufactured leadrather than a sub-element of a lead frame.

2. Description of the Related Art

There have been rapid advances in semiconductor technology, memorycapacity, and software development in recent years. Advances insemiconductor packaging, interconnect technologies, and printed circuitboard (PCB) assemblies have been more modest. The size of thesemiconductor package and the number of leads it can accommodate are nowmajor limiting factors determining computer speed and functionality.There is a trade-off between fabricating semiconductor packages with anincreased number of leads and the resulting increase in component size.More leads mean a faster and more efficient transfer of information;however, more leads take up more space, thus increasing costs, andslowing down the electrical signal as it travels to interface with otherdevices.

With respect to semiconductor packages, many different shapes and sizesare currently available. Conventional semiconductor package technologiesinclude the laminated ceramic technology, the pressed ceramictechnology, and the molded plastic technology.

In accordance with the laminated ceramic technology, a semiconductor dieis attached to a ceramic package having leads from a lead frameextending therefrom. Bonding pads on the die are connected to the leadsusing bonding wires. A cap is then glued to the ceramic package, therebysealing the die and inner portions of the leads within the package.

In pressed ceramic technology, a semiconductor die is attached to alower portion of a ceramic package having leads from a lead frameextending therefrom. After the wire bonding procedure, a top portion ofthe ceramic package is glued to the lower portion of the ceramic packageto seal the die and inner portions of the leads within the package.

In molded plastic technology, a semiconductor die is configured forhousing within a plastic package from which a set of leads will extend.In the initial stages of fabrication, the die is attached at a positionsurrounded by the leads from a lead frame. Wire bonding then takesplace, and thereafter an injection molding process is carried out toform a plastic package within which the die and inner portions of theleads are sealed. The leads are then bent to form the finished package.The steps required to form a conventional molded plastic package may beunderstood more fully from the flowchart depicted in FIG. 1.

As can be understood from FIG. 2, conventional package leads aretypically configured for mounting (on a PCB, for example) usingplated-through-hole (PTH) technology or surface-mount technology (SMT).

In PTH technology, a conductive PTH is formed in a PCB. Each lead of apackage is inserted through a corresponding PTH and then soldered toform a solder joint fastening the lead in conductive contact with thePTH.

In SMT mounting, each lead of a package, rather than being soldered toextend through a PTH in a PCB, is soldered onto a conductive portion ofa top surface of the PCB. If the package is a leadless die carrier, aconductive section of the package is soldered onto a conductive portionof a top surface of the PCB known as a bonding pad. A solder joint thenmaintains each lead of the leaded die carrier, or each conductivesection of the leadless die carrier, in a fastened relationship withrespect to the PCB. In accordance with SMT mounting, each lead of aleaded die carrier can have a “Gullwing” configuration; a “J-Lead”configuration; or a “Butt Lead” configuration.

Various conventional PTH and SMT packages are shown in FIG. 2. The PTHpackages include a DIP (Dual In-line Package); an SH-DIP (Shrink DIP);an SK-DIP (Skinny DIP) or SL-DIP (Slim DIP); an SIP (Single In-linePackage); a ZIP (Zig-zag In-line Package); and a PGA (Pin Grid Array).The SMT packages include an SO or SOP (Small Out-line Package); a QFP(Quad Flat Package); a LCC (Leadless Chip Carrier); and a PLCC SOJ(Plastic Leaded Chip Carrier with Butt Leads).

QFPs such as the ones shown in FIG. 2 are typically manufactured usingthe molded plastic technology described above. Most QFPs aremanufactured using a single-layer lead frame providing a single row ofbent leads extending from each of the four sides of the QFP.

Multi-row lead configurations are also known. For example, it is knownto provide two rows of leads, formed by using two different lead framesvertically spaced and insulated from each other, extending from sides ofa QFP. It is also known to provide rows of multiple leads formed usingvertically spaced lead frames with adjacent rows of leads primarilyseparated from each other by a gaseous dielectric such as air. Withrespect to the wire bonding procedure associated with conventionalsemiconductor die packages, it is known in PGA packages to positionbonding pads on different stepped levels.

The aforementioned semiconductor die packages suffer from manydeficiencies. QFP technology, for example, is severely limited for avariety of reasons. For example, the molded plastic technology typicallyused to manufacture QFPs incorporates various processes following thewire bonding procedure which can have detrimental effects on the bondingintegrity. These processes include sealing, which involves high-pressureinjection-molding and cooling/heating steps, and the bending of theleads to achieve desired lead configurations, whereby bonding wiremovement, breakage, and/or shorting can all result. Moreover, theencapsulation process is limited to the use of molding compounds withlow thermal conductivity which can result in performances at less thanan optimum level.

The use of lead frames during the manufacturing of QFP semiconductorpackages and the like also results in numerous disadvantages. First ofall, the types of dies from which conventional lead frames are stampedcan be very expensive because of the number of intricate featuresinvolved and the amount of the material that must be handled. Moreover,the manufacturing tolerances required in stamping the larger sizes ofnecessary elements cause the stamping of lead frames to be a low-yieldprocess. Also, packages which incorporate lead frames are typicallytested after die placement at a point so late in the manufacturingprocess that if the package turns out to be defective, any value thatmay have been added is rendered useless. Additionally, lead framestypically limit the die placement process to procedures such assingle-row peripheral pad bonding or tape automated bonding (TAB),thereby resulting in limitations in die placement options andflexibility. Furthermore, once a conventional QFP is completed, it isvery difficult, if not impossible, to carry out repairs on one or moreof the components of the package. In general, for conventional packagingtechnology, as the number of required leads increases, based onincreases in the speed and functionality of the relevant die, so doesthe size of the lead frame, increasing its manufacturing and toolingcosts and decreasing its efficiency due to the increased distances thesignal must travel.

QFP-type packages also tend to take up large amounts of PCB area, due inpart to the use of lead frames during their manufacture. For example,QFPs manufactured using a single-level lead frame and, therefore,including only a single row of leads extending from the sides of theQFP, typically require approximately 900 square millimeters of PCB areafor a 208-pin QFP, and approximately 1,832 square millimeters of areafor a 304-pin QFP.

Multi-row lead frame packages, to some extent, take up less PCB area interms of the number of leads that can be provided. However, variouslimitations can render conventional multi-row leaded packages unsuitablefor existing and contemplated packaging needs. Conventional structure,for example, is typically limited to two rows of leads per side, and allof the leads of both rows must be offset so that surface mounting can beperformed in accordance with conventional mounting technology. Suchcharacteristics can unnecessarily increase the amount of PCB area thatwill be required for mounting. Moreover, lead frames are typically usedduring the manufacture of the aforementioned conventional structure and,therefore, such structure is subject to a compounding of the inherentperformance limitations and additional complexity, noted above.

PGA packages having a stepped configuration are also subject tolimitations. For example, PGAs, unlike QFPs, are not generally suitablefor SMT applications. Instead, PGAs are typically mounted using PTHtechnology or are plugged into a socket. Also, PGAs take up significantamounts of PCB space and space and volume of the PCB and, consequently,can be an impediment to the manufacture of high-density circuitconfigurations. Moreover, PGAs are typically expensive due to the costof the ceramic package material and the brazed pin assembly that areused.

From the foregoing, it can be understood that conventional semiconductorpackages take up large amounts of board space; are expensive and oftenexperience difficulties during manufacture; perform insufficiently dueto procedures carried out after chip attachment and wire bonding thattend to inhibit bond integrity; and, after manufacture, are difficult,if not impossible, to repair. As a result of such limitations, currentsemiconductor packaging technology is not sufficient to meet the needsof existing and/or future semiconductor and computer technology.Semiconductor packaging technology has already failed to keep pace withsilicon die technology, and as computer and microprocessor speedscontinue to climb, with space efficiency being increasingly important,semiconductor die packages having even smaller area requirements will berequired. The semiconductor die packages discussed above fall short ofcurrent and contemplated semiconductor and computer requirements.

SUMMARY OF THE INVENTION

Accordingly, it is a goal of the present invention to provide aprefabricated semiconductor die carrier occupying reduced amounts ofboard area, providing an increased number of contacts, and capable ofmeeting the needs of existing and contemplated semiconductor andcomputer technology.

Another goal of the present invention is to provide a semiconductor diecarrier manufactured without the use of lead frames and having leadsextending from side portions thereof suitable for mounting using PTHtechnology, SMT methodology, or pluggable mounting.

Yet another goal of the present invention is to provide a semiconductordie carrier wherein a semiconductor die is bonded from multiple rows ofpads on the die to vertically spaced rows of multiple leads whilemaintaining a very low profile package.

Still another goal of the present invention is to provide asemiconductor die carrier that is fabricated and tested prior toplacement of a semiconductor die within the carrier, thereby increasingfinal packaging yields and reducing total unit cost.

A further goal of the present invention is to provide a semiconductordie carrier wherein the leads are configured to facilitate the routingof PCB traces for connection to the leads.

It is also a goal of the present invention to provide methods for makingand using semiconductor die carriers having characteristics such asthose discussed above.

These and other goals may be achieved by using a semiconductor diecarrier comprising a plurality of electrically insulative side walls; aplurality of electrically conductive leads extending from at least oneof the side walls, each of the leads being individually manufacturedwithout use of a lead frame; a semiconductor die positioned such thatthe electrically conductive leads are disposed at one or more locationsaround the periphery of the die; and means for providing electricalconnection between the semiconductor die and corresponding ones of theelectrically conductive leads.

Also, a method of manufacturing a semiconductor die carrier may be used,the method comprising the steps of individually manufacturing aplurality of conductive leads without use of a lead frame; extending aplurality of the electrically conductive leads from at least one of aplurality of electrically insulative side walls; positioning asemiconductor die such that the electrically conductive leads aredisposed at one or more locations around the periphery of the die; andelectrically connecting the semiconductor die to corresponding ones ofthe electrically conductive leads.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory, andare not restrictive of the invention as claimed. The accompanyingdrawings, which are incorporated in and constitute a part of thespecification, illustrate embodiments of the present invention and,together with the general description, serve to explain the principlesof the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating steps in a conventional method formanufacturing a semiconductor package.

FIG. 2 is a view showing conventional PTH and SMT semiconductorpackages.

FIG. 3 is a perspective view of a two-tier embodiment of a prefabricatedsemiconductor die carrier in accordance with the present invention.

FIG. 4 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 3.

FIG. 5 is a perspective view of a twelve-sided semiconductor die carrierin accordance with the present invention.

FIG. 6 is a partial perspective view of an eight-sided semiconductor diecarrier in accordance with the present invention.

FIG. 7(a) is a perspective view of a two-row embodiment of aprefabricated semiconductor die carrier in accordance with the presentinvention prior to the fastening of the side walls to one another andthe floor.

FIG. 7(b) is a perspective view of a two-row embodiment of aprefabricated semiconductor die carrier in accordance with the presentinvention prior to the fastening of the side walls to one another andthe floor.

FIG. 8(a) is a perspective view of an SMT lead with an L-shaped footportion configured in accordance with the present invention andpositioned on a bonding pad of a multi-layer conductor such as a PCB.

FIG. 8(b) is a perspective view of an SMT lead in accordance with thepresent invention having an L-shaped foot portion and a horizontalstability portion.

FIG. 9 is a perspective view of another SMT lead with an L-shaped footportion configured in accordance with the present invention.

FIG. 10 is a partial perspective view of a conductive lead inserted intoa side wall including insulative structure for preventing over-insertionof the lead.

FIG. 11 is a perspective view of another SMT lead with an L-shaped footportion configured in accordance with the present invention.

FIG. 12 is a perspective view of an SMT lead with a straight or ButtLead foot portion configured in accordance with the present invention.

FIG. 13 is a perspective view of a PTH lead configured in accordancewith the present invention.

FIG. 14 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 3.

FIG. 15 is a perspective view of a three-tier embodiment of aprefabricated semiconductor die carrier in accordance with the presentinvention.

FIG. 16 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 15.

FIG. 17 is a partial side view of the embodiment of the semiconductordie carrier illustrated in FIG. 15 prior to lead insertion with a dottedline segmenting repeating sets of passage arrangements.

FIG. 18 is a partial side view of the embodiment of the semiconductordie carrier illustrated in FIG. 15 after lead insertion with a dottedline segmenting repeating sets of contact arrangements.

FIG. 19 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 15 showing wire bondingdetails.

FIG. 20 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 15 showing lead interfacedetails.

FIG. 21 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 15 showing lead interfacedetails.

FIG. 22 is a partial top view of the embodiment of the semiconductor diecarrier illustrated in FIG. 15 showing footprint details with a dottedline segmenting repeating sets of contact arrangements.

FIG. 23 is a partial top view of the embodiment of the semiconductor diecarrier illustrated in FIG. 15 showing lead interface details with adotted line segmenting repeating sets of contact arrangements.

FIG. 24 is a partial side view of the embodiment of the semiconductordie carrier illustrated in FIG. 15 including a cap.

FIG. 25 is a partial side view of a cavity-down configuration inaccordance with the embodiment of the semiconductor die carrierillustrated in FIG. 15.

FIG. 26 is a partial side view of a die indentation configuration inaccordance with the embodiment of the semiconductor die carrierillustrated in FIG. 15 including a cap.

FIG. 27 is a partial side view of a same or similar level configurationin accordance with the embodiment of the semiconductor die carrierillustrated in FIG. 15 including a cap.

FIG. 28 is a partial side view of a platform configuration in accordancewith the embodiment of the semiconductor die carrier illustrated in FIG.15 including a cap.

FIG. 29(a) is a partial perspective view of a four-tier embodiment of aprefabricated semiconductor die carrier in accordance with the presentinvention.

FIG. 29(b) is a partial perspective view of a three-tier embodiment of aprefabricated semiconductor die carrier in accordance with the presentinvention.

FIG. 30 is a partial side view of the embodiment of the semiconductordie carrier illustrated in FIG. 29(a) prior to lead insertion with adotted line segmenting repeating sets of passage arrangements.

FIG. 31 is a partial side view of the embodiment of the semiconductordie carrier illustrated in FIG. 29(a) after lead insertion with a dottedline segmenting repeating sets of contact arrangements.

FIG. 32 is a partial perspective view of the embodiment of thesemiconductor die carrier illustrated in FIG. 29(a) showing leadinterface details.

FIG. 33(a) is a partial perspective view of a multiple-wallconfiguration in accordance with the embodiment of the semiconductor diecarrier illustrated in FIG. 29(a).

FIG. 33(b) is a perspective view of a lead having a stabilizing sectionwith a notched portion configured for use with a multiple-wallconfiguration in accordance with the present invention.

FIG. 33(c) is a perspective view of a lead having a stabilizing sectionwith a raised portion configured for use with a multiple-wallconfiguration in accordance with the present invention.

FIG. 33(d) is a partial perspective view of the lead of FIG. 33(c)formed within a multiple-wall configuration of a semiconductor diecarrier in accordance with the present invention.

FIG. 34 is a partial top view of the embodiment of the semiconductor diecarrier illustrated in FIG. 29(a) showing footprint details with adotted line segmenting repeating sets of contact arrangements.

FIG. 35 is a partial top view of the embodiment of the semiconductor diecarrier illustrated in FIG. 29(a) showing lead interface details with adotted line segmenting repeating sets of contact arrangements.

FIG. 36 is a partial perspective view of an insulating separatorconfiguration in accordance with the embodiment of the semiconductor diecarrier illustrated in FIG. 29(a).

FIG. 37 is a partial side view of an insulating separator configurationin accordance with the embodiment of the semiconductor die carrierillustrated in FIG. 29(a) including a cap.

FIG. 38 is a partial side view of a configuration in accordance with thepresent invention having a stepped ceramic component to facilitatebonding of smaller dies having large I/O characteristics.

FIG. 39(a) is a partial side view of a configuration in accordance withthe present invention having non-coplanar leads to facilitate mountingon a multi-layer conductor such as a multi-layer PCB.

FIG. 39(b) is a partial perspective view of a semiconductor die carrierin accordance with the present invention having coplanar andnon-coplanar leads to facilitate mounting on a multi-layer conductorsuch as a multi-layer PCB.

FIG. 40 is a partial perspective view of a prefabricated semiconductordie carrier in accordance with the present invention having leadpassages with rounded corners.

FIG. 41 is a perspective view of a multi-die configuration of aprefabricated semiconductor die carrier in accordance with the presentinvention.

FIG. 42 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention having upwardly-oriented anddownwardly-oriented leads.

FIG. 43 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention having sideways-extending anddownwardly-extending leads.

FIG. 44 is a partial bottom view of a prefabricated semiconductor diecarrier in accordance with the present invention having a nestedconfiguration of downwardly-extending leads.

FIG. 45 is a partial bottom view of a prefabricated semiconductor diecarrier in accordance with the present invention having a modifiedarrangement of downwardly-extending leads.

FIG. 46 is a partial bottom view of a prefabricated semiconductor diecarrier in accordance with the present invention having a nestedarrangement of downwardly-extending leads.

FIG. 47(a) is a partial bottom view of a prefabricated semiconductor diecarrier in accordance with the present invention having a modifiedarrangement of downwardly-extending leads.

FIG. 47(b) is a partial bottom view of a prefabricated semiconductor diecarrier in accordance with the present invention including anarrangement of downwardly-extending leads arranged in groups havingH-shaped spaces incorporated therein.

FIG. 48 depicts a pair of flowcharts comparing a conventionalmanufacturing method with a method in accordance with the presentinvention performed in order to manufacture, transport, and mount aprefabricated semiconductor die carrier.

FIG. 49(a) is a perspective view of leads in an upright position on abandolier during a manufacturing process in accordance with the presentinvention.

FIG. 49(b) is a perspective view of leads positioned sideways on abandolier during a manufacturing process in accordance with the presentinvention.

FIG. 50 is a perspective view of a first type of transportationpackaging in accordance with the present invention.

FIG. 51 is a perspective view of the first type of packaging shown inFIG. 50 with a semiconductor die carrier residing therein.

FIG. 52 is a partial perspective view of the first type of packagingshown in FIG. 50 with a semiconductor die carrier residing therein.

FIG. 53 is a partial perspective view of the first type of packagingshown in FIG. 50 with another semiconductor die carrier residingtherein.

FIG. 54(a) is a side view of a second type of transportation packagingin accordance with the present invention.

FIG. 54(b) is a perspective view of a semiconductor die carrierparticularly well-suited for use with the type of transportationpackaging illustrated in FIG. 54(a).

FIG. 55 is a perspective view of a third type of transportationpackaging in accordance with the present invention.

FIG. 56 is a perspective view of a pluggable lead configured inaccordance with the present invention.

FIG. 57 is a partial perspective view of the semiconductor die carrierin accordance with the present invention plugged within a pluggablesocket.

FIG. 58 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention plugged within another pluggablesocket.

FIG. 59 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention plugged into the pluggable socketillustrated in FIG. 58.

FIG. 60 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention having leads extending straightout of one or more sides of the carrier.

FIG. 61 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention including leads having analternate foot configuration.

FIG. 62 is a top view of a single-tier embodiment of a semiconductor diecarrier in accordance with the present invention.

FIG. 63 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention wherein the leads of at least onerow alternate with vias extending into a substrate such as a PCB.

FIG. 64 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention showing an arrangement of bondingextensions inside the carrier.

FIG. 65 is a perspective view of a rounded lead configured in accordancewith the present invention.

FIG. 66 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention having round lead passages.

FIG. 67 is a chart comparing various embodiments in accordance with thepresent invention with conventional QFP technology.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A prefabricated semiconductor die carrier in accordance with the presentinvention has multiple rows of electrically conductive leads arranged atvertically spaced multiple levels around the periphery of the carrier.Such leads may also be arranged on the top or bottom of the carrier.Each of the leads is manufactured and assembled into the semiconductordie carrier prior to the die attach step as an individually manufacturedlead, rather than as a sub-element of a lead frame, to facilitate themultiple-row, multiple-level structure.

The leads of the semiconductor die carrier may be offset from otherlevels at the point where the leads extend through side walls of thecarrier and/or staggered at the point where the leads connect to a PCBor other interface surface. At least the latter configuration allowstraces on the PCB to be routed between the staggered leads.

The leads of the semiconductor die carrier extend into the die carrierthrough the side walls of the die carrier, forming a series ofvertically spaced rows of multiple leads around the semiconductor die.The portions of the leads extending through the side walls have wirebond terminals formed thereon. A wire bond insulator may be used toseparate the rows of leads. The semiconductor die can be mounted withinthe carrier with the peripheral pads of the die facing up and away fromthe PCB, in a cavity-up configuration, or with the peripheral pads ofthe die facing down toward the PCB, in a flip-chip or cavity-downconfiguration.

Encapsulation for the semiconductor die carrier of the present inventionis performed by filling the die cavity with an epoxy, a liquid crystalpolymer such as VECTRA (a trademark of Hoechst Celanese) or otherhigh-temperature material. The semiconductor die carrier may be cappedwith a plastic component or thermally conductive cap that serves as aheat sink.

The semiconductor die carrier of the present invention provides apackage having a reduced size as compared to known semiconductorpackages, yet increases the number of interconnects available for thedesigner and user. The die carrier may be pluggable or compatible witheither the PTH or SMT methodology. The semiconductor die carrier isprefabricated and tested prior to introduction of the semiconductor dieto the carrier, thereby increasing finished product yields and reducingtotal unit cost. The configuration of the die carrier allows thesemiconductor die to be bonded from multiple rows of pads on the die tomultiple levels of vertically spaced rows of leads while maintaining avery low profile for the die carrier.

The semiconductor die carrier of the present invention provides bettercoplanarity of the feet of the leads when mounting using the SMTmethodology, for example, thereby avoiding non-contact between the leadsand the surface of the PCB. Such coplanarity is not always possibleusing conventional packaging technology due to the bending of the leadsthat is required when using a lead frame.

Details relating to the present invention will now be discussed withreference to the accompanying drawings. For the sake of convenience, thesame reference numerals will be used to designate the same or similarcomponents of the present invention in the accompanying drawings.

A perspective view of an embodiment of a prefabricated semiconductor diecarrier in accordance with the present invention is shown in FIG. 3. Apartial view of the embodiment of FIG. 3 is shown in FIG. 4. Inaccordance with the embodiment of FIG. 3, the semiconductor die carrierincludes a semiconductor die 101; an insulating substrate 102, having afloor 102 a and a plurality of side walls 102 b; a plurality of leads103, including lower leads 103 a and upper leads 103 b; a plurality ofbonding pads 104 formed on the semiconductor die; a plurality of bondingterminals 105 formed on the leads 103, respectively; and a plurality ofbonding wires 106 each connecting at least one of the bonding pads 104of the die to a corresponding one of the bonding terminals 105 formed onthe leads.

While the semiconductor die and semiconductor die carrier of theembodiment of FIG. 3 are depicted as being square, both thesemiconductor die and the die carrier could assume another shape, suchas a rectangle having sides of different lengths. Also, the number ofsides the semiconductor die carrier can be varied, such that diecarriers having twelve sides, for example, as depicted in FIG. 5, oreight sides, for example, as depicted in FIG. 6, are within the scope ofthe present invention. The die carriers of FIGS. 5 and 6 are designed totake up less space than four-sided die carriers and, as shown in FIG. 6,additional leads can be provided on the additional sides to achieve evengreater efficiency. In accordance with the configuration of FIG. 6, forexample, forty extra leads may be provided by positioning ten additionalleads within each of the additional side walls. Moreover, while thesemiconductor die carrier has been shown having two rows of leads 103,only a single row of leads could be used, or more than two rows of leadswould be used, as discussed in greater detail below.

The semiconductor die 101 of the semiconductor die carrier can be asemiconductor die having a single row of bonding pads 104 arranged alongeach of its edges, as shown in FIG. 3, or a semiconductor die having,for example, two or more rows of bonding pads arranged along each of itsedges. In the latter situation, the bonding pads 104 could be arrangedin straight rows and columns, or the bonding pads 104 could be arrangedin some other configuration, for example, arranged such that the bondingpads from adjacent rows are staggered.

The insulating substrate 102 of the semiconductor die carrier is made ofa liquid crystal polymer or material having properties the same orsimilar to a liquid crystal polymer. Preferably, the liquid crystalpolymer for the insulating substrate 102 is VECTRA (trademark), whichhas a coefficient of thermal expansion that is approximately the same asor similar to the coefficient of thermal expansion for silicon.

The insulating substrate 102 may be formed in a molding process carriedout prior to inserting the leads 103 into the side walls 102 b ofsubstrate, and prior to mounting the die 101 onto the floor 102 a of thesubstrate. During the molding process, a series of lead holes orpassages 107 are molded within the side walls 102 b of the substrate,each of the passages for receiving a corresponding one of the leads 103,and a series of ledges 108 are formed inside the side walls of thesubstrate around the periphery where the die is to be placed. The ledges108 serve to support the leads 103 (during the wire bonding procedure,for example). As an alternative to forming the lead passages 107 andledges 108 during the molding process, the lead passages and/or ledgescould be added after molding by, for example, removing material of thesubstrate to form the lead passages and/or by applying insulativematerial (using an adhesive or epoxy, for example) to form the ledges.

Moreover, rather than being formed integrally in a single moldingprocess, the floor 102 a and side walls 102 b could be moldedseparately, and then fastened together using an adhesive or epoxymaterial. In this case, the leads 103 could be inserted into the sidewalls 102 b either before or after the fastening of the side walls toone another or to the floor 102 a. FIG. 7(a) is a view showing anexample of the leads 103 inserted into the side walls 102 b prior to thefastening of the side walls to one another and to the floor 102 a. FIG.7(b) illustrates that steps or notches may be molded on the bottomand/or corners of the side walls 102 b and on the sides of the floor 102a to increase the glue area and surface area where the floor 102 a andside walls 102 b meet, thereby facilitating the formation of a strongerbond.

The leads 103 are inserted into the side walls 102 b of the substrate102 after formation of the lead passages 107 and ledges 108. The leads103 may be inserted individually one-by-one, or “gang-inserted” ingroups. For example, in accordance with gang-inserting, all of the leads103 for each side of the semiconductor die carrier could be insertedsimultaneously, or all of the lower leads 102 a could be insertedsimultaneously followed by a simultaneous insertion of the upper leads103 b above such lower leads.

The direction of lead insertion may be, for each side wall 102 b, fromthe outer surface of the side wall toward the inner surface of the sidewall. Each of the leads 103 is inserted into a corresponding one of thelead passages 107. The dimensions of the leads 103 and lead passages 107are such that each lead 103 fits tightly within its corresponding leadpassage 107. However, if desired, each lead 103 can be further fastenedwithin its corresponding lead passage 107 and/or onto a correspondingledge 108 using an epoxy or other adhesive material.

As an alternative to molding the side walls 102 b and then inserting theleads 103 into the side walls, the leads may be formed within the sidewalls using an insert molding process. In accordance with insertmolding, the leads 103 are supported by a bandolier or other fixture,and then the insulative substrate 102 or, alternatively, only the sidewalls 102 b of the insulative substrate, are molded around the leads.After completion of the molding process, the resulting structure isextracted from the mold. If the resulting structure is a side wall withleads formed therein, that side wall is fastened together with otherside walls and a floor to form the insulative substrate containing theleads. If the resulting molded structure is an insulative substratealready including a floor and a plurality of side walls, then no furtherfastening of the side walls to one another or to the floor is required.

In the embodiment of FIG. 3, the lower leads 103 a and upper leads 103 bare similarly shaped, although the vertically-extending sections of thelower leads are shorter than the vertically-extending sections of theupper leads. The horizontally-extending sections of the lower leads 103a could be longer, shorter, or the same length as thehorizontally-extending sections of the upper leads 103 b.

In the embodiment of FIG. 3, the lower leads 103 a and upper leads 103 bare aligned in a straight line with respect to one another rather thanstaggered. In other words, for each upper lead 103 b, a correspondinglower lead 103 a is positioned directly beneath that upper lead. Whilenot shown in FIG. 3, the lower leads 103 a and upper leads 103 b couldbe staggered with respect to one another. In a staggered configuration,none of the lower leads 103 a would be beneath any of the upper leads103 b. Instead, progressing along a given one of the side walls 102 b,every other lead would be a lower lead 103 a or an upper lead 103 b.

A perspective view of an example of one of the leads 103 is shown inFIG. 8(a). As seen from FIG. 8(a), each of the leads 103 includes abonding extension section 1031 having a bonding terminal 105 formed onan end portion thereof; a stabilizing section 1032; and an external leadsection 1033. Each lead 103 may be formed of beryllium copper, phosphorbronze, brass, a copper alloy, tin, gold, palladium, or any othersuitable metal or conductive material, and the bonding terminal 105 maybe a gold-plated pad or pad formed of another suitable conductivematerial.

The bonding extension section 1031 is a relatively long and narrowportion of the lead 103 which protrudes toward the interior of thesemiconductor die carrier from the inner surface of a corresponding oneof the side walls 102 b. The lower surface of the bonding extensionsection 1031 is supported by the floor 102 a of the substrate if thelead is a lower lead 103 a, or is supported by a corresponding one ofthe ledges 108 if the lead is an upper lead 103 b. Alternatively, thesubstrate 102 can be formed without ledges, in which case the upperleads would be suspended in air above the floor 102 a rather than beingsupported by a ledge. The bonding terminal 105 may be, for example, abonding pad to which a bonding wire 106 for attachment to acorresponding bonding pad 104 on the die 101 can be connected.

The stabilizing section 1032 of each lead 103 is the portion of the leadthat is anchored within a side wall 102 b of the substrate 102. Thestabilizing section has a larger cross-sectional area than that of thebonding extension section 1031 and may also have a largercross-sectional area than that of the external lead section 1033. Thethick stabilizing section retains the lead and prevents forces exertedon the external lead section from transferring to the bonds associatedwith bonding wire 106. As in FIG. 8(a), for example, the stabilizingsection 1032 may be taller than the bonding extension section 1031 andthe external lead section 1033. Likewise, the stabilizing section 1032could be wider than the bonding extension section 1031 and the externallead section 1033, as in FIG. 8(b), or both wider and taller than thebonding extension section 1031 and the external lead section 1033. Theconfiguration of FIG. 8(b), for example, allows the semiconductor diecarrier to be manufactured lower in height since the wider part isarranged horizontally. In addition to the aforementioned configurations,the stabilizing section 1032 could be the same size in cross-section asthe bonding extension section 1031 and the external lead section 1033.FIG. 9 shows that the stabilizing section 1031 could be the same size incross-section as the external lead section 1033 while, at the same time,having a height that is different than that of the bonding extensionsection 1031.

As seen most clearly in FIG. 4, each 103 lead can be positioned so thatthe inwardly-facing surface of that part of the stabilizing section 1032which is higher than the bonding extension section 1031 is level orflush with the inner surface of its corresponding side wall 102 b.Alternatively, as can be understood from FIG. 10, the lead passage 107for each lead 103 can be narrowed at the end of the passage locatednearest the interior of the carrier (for example, only narrow enough toallow passage of the bonding extension section 1031 through the sidewall 102 b of the substrate) so as to prevent the lead from beinginserted too far into the side wall of the substrate. In this situation,after full insertion of each lead 103, a section of insulative substratematerial would exist for each lead between the inner surface of thecorresponding side wall 102 b and the inwardly-facing surface of thatpart of the stabilizing section 1032 higher than the bonding extensionsection 1031.

As seen from FIG. 11, the upper surface of each lead 103 may be slopedat the juncture between the bonding extension section 1031 and thestabilizing section 1032, to allow for ease of insertion into itscorresponding lead passage 107. The sloped surface may also serve toprevent over-insertion of the lead 103 if the corresponding lead passage107 is modified to be narrowed or tapered at the end of the passagelocated nearest the interior of the carrier. The narrowing or taperingat the end of the lead passage 107 could occur at a slope correspondingto that of the sloped surface of the lead 103 to allow for a tight fitof the lead within its corresponding passage.

For the lead 103 shown in FIG. 8(a), the lower surface of thestabilizing section 1032 and the lower surface of the bonding extensionsection 1031 are level, but the upper surfaces of these sections are notlevel. Also, in the lead 103 of FIG. 8(a), the upper and lower surfacesof the stabilizing and external lead sections are not level. However,each lead could be configured so that the bonding extension section 1031extends from a middle section of the stabilizing section 1032 (like theexternal lead section 1033 shown in FIG. 8(a)) or from an upper sectionof the stabilizing section 1032 (such that the upper surfaces of thebonding extension section 1031 and stabilizing section 1032 would belevel, for example). Also, each lead 103 could be configured so that theexternal lead section 1033 extends from a lower section of thestabilizing section 1032 (like the bonding extension section 1031 shownin FIG. 8(a), which has a lower surface that is level with respect tothe lower surface of the stabilizing section 1032) or from an uppersection of the stabilizing section 1032 (such that the upper surfaces ofthe external lead section 1033 and stabilizing section 1032 would belevel, for example).

The external lead section 1033 includes a horizontally-extending section1033 a, a corner section 1033 b, a vertically-extending section 1033 c,and a foot section 1033 d. The configuration and length of thehorizontally-extending and vertically-extending sections for eachindividual lead 103 are selected based on design requirements and, inparticular, based on whether that lead will be used as a lower lead 103a or an upper lead 103 b. The horizontally-extending sections 1033 a ofthe upper leads 103 b may be longer than the horizontally-extendingsections of the lower leads 103 a, and the vertically-extending sections1033 c of the upper leads may be longer than the vertically-extendingsections of the lower leads.

As seen from FIG. 8(a), for each lead 103, the horizontally-extendingsection 1033 a of the external lead section 1033 extends out of thestabilizer section 1032 in a direction away from the outer surface ofthe corresponding side wall 102 b. The external lead section 1033 bendsdownward at a corner section 1033 b between the horizontally-extendingsection 1033 a and the vertically-extending section 1033 c. Thevertically-extending section 1033 c terminates in a foot section 1033 d.The PCB contact surface for the foot section 1033 d may have a largercross-section than that of the vertically-extending section 1033 c, asshown in FIG. 8(a), or, alternatively, may have a Butt Leadconfiguration, as shown in FIG. 12, such that the cross-section of thecontact surface for the foot section is the same as that of thevertically-extending section.

The foot sections 1033 d shown in FIGS. 8(a) and 12 are configured formounting to a PCB or other interface surface in accordance with SMTmethodology. Alternatively, foot section 1033 d could be configured formounting in a PCB or the like in accordance with PTH technology, asshown in FIG. 13, for example.

With reference to FIG. 14, after all of the leads 103 are formed in theside walls 102 b of the carrier and electrically and mechanically tested(for retention, continuity, coplanarity, and the like), thesemiconductor die 101 is adhered to the floor 102 a of the substrate 102using an adhesive, epoxy, or the like. Thereafter, the bonding pads 104on the die 101 are bonded or connected to bonding terminals 105 on thebonding extension sections 1031 of the leads 103, respectively, toprovide a conductive path from the semiconductor die 101 to the externallead sections 1033 of such leads. FIG. 14, which is another partial viewof the semiconductor die carrier shown in FIG. 3, depicts an example ofthe connection of a first die bonding pad 104 a to the bonding terminal105 on a lower lead 103 a, and the connection of a second die bondingpad 104 b to the bonding terminal 105 on an upper lead 103 b. Each ofthese connections occurs via a bonding wire 106. Such bonding wireconnections may be performed for all of the bonding pads 104 formed onthe die 101.

After the wire bonding procedure, encapsulation may be carried out byfilling the cavity defined by the floor 102 a and the side walls 102 bof the substrate 102 with epoxy, a liquid crystal polymer such as VECTRA(trademark), or other high-temperature material. The semiconductor diecarrier might then be capped with a plastic component orthermally-conductive cap that may serve as a heat sink, and thereaftersealed. When this type of cap is used, the encapsulation step isoptional. The heat sink and high-temperature material which may be usedfor encapsulation facilitate the heat dissipation capabilities of thesemiconductor die carrier.

Dimensions of the semiconductor die carrier having two vertically spacedrows of multiple leads can be understood, for example, with reference tothe accompanying figures.

As can be seen from FIG. 3, for example, a two-row semiconductor diecarrier in accordance with the present invention may have, for example,a height of 2.0 mm, a width of 17.9 mm, and a lead row length of 8.7 mm.In this configuration, the semiconductor die carrier of the presentinvention can be manufactured to be approximately 64% smaller thanconventional 128-pin QFPs, and at the same time provides 16 extra leads.

From FIG. 8(a), it can be understood that a lead 103 in accordance withthe present invention may have a bonding extension section 1031 that is1.5 mm in length; a stabilizing section 1032 that is 1.0 mm in length,and an external lead section 1033 having a vertically-extending section1033 c that varies in length depending whether the lead is an upper leador a flower lead. In general, the lengths of the horizontally-extendingsections and vertically-extending sections 1033 a and 1033 c of eachlead, respectively, depend upon whether or not that lead is to be usedas a lower lead 103 a or an upper lead 103 b. However, if desired, thelengths of the horizontally-extending sections 1033 a of the upper andlower leads, respectively, could be the same, with only the lengths ofthe vertically-extending sections 1033 c-being different. As shown inFIG. 8(a), the foot section 1033 d of a lead 103 configured for mountingin accordance with SMT can have a cross-section of 0.2×0.4 mm, forexample, for mounting on a PCB bonding pad 109 having an exemplarycross-section of 0.4×0.6 mm. FIG. 14 illustrates that each ledge mayhave a height of 0.7 mm, for example.

A perspective view of another embodiment of a prefabricatedsemiconductor die carrier in accordance with the present invention isshown in FIG. 15. The embodiment of FIG. 15 essentially corresponds tothe embodiment shown in FIG. 3, except that three vertically spaced rowsof multiple leads 103 a, 103 b, and 103 c are used instead of two ofsuch rows. Such a configuration enhances the interconnect capabilitiesof the semiconductor die carrier. While not shown in FIG. 15, ledges 108might be applicable to the three-row semiconductor die carrier inaccordance with the present invention.

The semiconductor die carrier of FIG. 15 may be manufactured in the samemanner that the carrier shown in FIG. 3 is manufactured. Moreparticularly, for the embodiment of FIG. 15, the leads 103 are formedwithin the side walls 102 b via insertion or an insert moldingprocedure; the semiconductor die 101 is adhered to the floor 102 a; thebonding pads 104 of the die are connected to the bonding terminals 105of the leads 103, respectively; and the cavity of the carrier could befilled with high-temperature material such as VECTRA (trademark) and/ora cap could be sealed on top of the carrier. Exemplary dimensions forthe embodiment of FIG. 15 are a height of 2.7 mm; a width of 21.5 mm;and a lead row length of 11.8 mm. In this configuration, thesemiconductor die carrier of FIG. 15 can be configured to provide 208leads using approximately half of the area (for example, board area) ofthat required by conventional QFP technology.

FIG. 16 is a partial perspective view of the embodiment shown in FIG.15, illustrating details of the manner in which the leads 103 arearranged within the side walls 102 b of the substrate 102. FIG. 17 is apartial side view of the semiconductor die carrier of FIG. 15 prior toinsertion of the leads 103 into the lead passages 107, and FIG. 18 is apartial side view of the semiconductor die carrier of FIG. 15 afterinsertion of the leads 103. The patterns separated by dotted lines inFIGS. 17 and 18 may repeat along the length of each side wall 102 b.

The arrangement of the leads 103 within the side walls 102 b allows thebonding extension sections 1031 of the leads to be positioned tofacilitate the connecting of the bonding terminals 105 of the leads tothe bonding pads 104 on the semiconductor die. As seen from FIG. 19,which is a partial perspective view of the embodiment of FIG. 15 showingwire bonding details, a three-row embodiment of the present inventioncan be used for packaging in connection with a semiconductor die havingtwo or more rows of bonding pads 104 arranged along each of its edges.Alternatively, the semiconductor die could have a single row of bondingpads 104 aligned along each of its edges. It should be noted that whileledges 108 are not shown in FIG. 15, such ledges are applicable to thisembodiment.

FIGS. 20 and 21 are partial perspective views of the embodiment of FIG.15 illustrating details of the manner in which the leads 103 mayinterface with a PCB or other interface surface. FIG. 22 is a partialtop view showing only the foot sections 1033 d of the leads 103 arrangedon bonding pads 109 of a PCB or other interface surface. Theconfiguration illustrated in FIG. 22 will be referred to herein as afootprint of the semiconductor die carrier. FIG. 23 is a partial topview showing the manner in which the leads 103 extend from the exteriorsurface of the side walls 102 b for mounting on a PCB or other interfacesurface. The patterns separated by dotted lines in FIGS. 22 and 23 mayrepeat along the length of each side wall 102 b.

The arrangement of the leads 103 with respect to the PCB or otherinterface surface facilitates the routing of traces 110 on the interfacesurface upon which, if using SMT technology, for example, or withinwhich, if using PTH technology, for example, the semiconductor diecarrier is being mounted. As seen from FIGS. 20-23, for example, thefootprint of the semiconductor die carrier of FIG. 15 is arranged intothree rows. The first row “a” of the footprint, closest to the sidewalls 102 b of the carrier, is defined by the foot sections of the lowerleads 103 a. The second row “b” of the footprint, further from the sidewalls 102 b of the carrier, is defined by the foot sections of themiddle leads 103 b; and the third row “c” of the footprint, furthestfrom the side walls 102 b of the carrier, is defined by the footsections of the upper leads 103 c.

The footprint for the three-row embodiment in accordance with thepresent invention may be configured such that, for each row of thefootprint, the closest distance between adjacent foot sections is 0.3mm, and the closest center-line to center-line distance between adjacentfoot sections is 0.5 mm. This allows for the incorporation ofhigh-density interconnect availability on the PCB or other interfacesurface upon or within which the leads 103 will be mounted. Theaforementioned 0.3 and 0.5 mm distances may be applicable to the otherembodiments (for example, one-row, two-row, and four-row embodiments) ofthe present invention.

A partial side view of the embodiment of FIG. 15 is shown in FIG. 24.The illustration of FIG. 24 shows features of the semiconductor diecarrier including a die bond adhesive 111 for mounting the die 101 onthe floor 102 a; bonding wires 106 which, in each of the embodiments ofthe present invention, may be dimensioned to have a wire length of lessthan 1.0 to 2.5 mm, for example; a cavity filler 112 used to fill thecavity defined by the floor 102 a and side walls 102 b of the carrierduring the encapsulation process; and a sealing cap 113, made of plasticor other thermally-conductive material such as metal or VECTRA(trademark), and capable of functioning as a heat sink, for providing acover for the semiconductor die carrier.

FIGS. 25-28 show various configurations relating to the placement of thesemiconductor die 101 within the semiconductor die carrier. AlthoughFIGS. 25-28 depict an embodiment having three-row configuration, itshould be noted that the die placement configurations illustrated inthese figures are also applicable to the other embodiments of thepresent invention, including the one-row and two-row embodimentsdiscussed above and the four-row embodiments discussed below.

Where FIG. 24 corresponds to a cavity-up configuration, in which thesemiconductor die is mounted within the carrier with the peripheral padsof the die facing up and away from the PCB or other mounting surface,FIG. 25 corresponds to a cavity-down or flip-chip configuration, inwhich the peripheral pads of the die face down toward the PCB or otherinterface surface. In the configuration of FIG. 25, the die 101 ismounted on a heat sink cap 114, preferably formed of a thermallyconductive material, and then wire bonding, encapsulation, and sealingusing a sealing cap 113, preferably formed of VECTRA (trademark), takeplace. The heat sink cap 114 can be an integrally molded component ofthe substrate 102, or attached to the substrate 102 after molding of thesubstrate is completed.

FIG. 26 shows that the semiconductor die 101 may be embedded or placedinto an indentation, similar to the size of the semiconductor die,formed in the floor 102 a for receipt of the die. In this configuration,the top surface of the die is located below the bonding extensionsections 1031 of the lower leads 103 a.

FIG. 27 shows the placement of the semiconductor die 101 on top of aflat floor 102 a. In this configuration, the top surface of thesemiconductor die 101 is the same level or similar in height to theheight of the bonding extension sections 1031 of the lower leads 103 a.

FIG. 28 shows the placement of the semiconductor die 101 on a raisedplatform 115, similar to the size of the die, formed in the interior ofthe semiconductor die carrier. The raised platform 115 may be anintegrally molded component of the substrate 102, or attached to thesubstrate 102 after molding of the substrate is completed.

It should be noted that, in each of the configurations shown in FIGS.25-28, the semiconductor die 101 may be mounted using an adhesivematerial, epoxy, or the like.

A partial view of another embodiment of a preferred semiconductor diecarrier in accordance with the present invention is shown in FIG. 29(a).FIG. 29(b) shows a semiconductor die carrier similar to the one shown inFIG. 29(a), except that the ledges 108 in FIG. 29(b) fill in the gapsbetween adjacent leads of the same row, and only three rows of leads areshown in FIG. 29(b). In other words, in FIG. 29(b), the ledges 108 arenot undercut. This simplifies the carrier mold.

The embodiment of FIG. 29(a) essentially corresponds to the embodimentsshown in FIGS. 3 and 15, for example, except that four vertically spacedrows of multiple leads 103 a, 103 b, 103 c, and 103 d are used insteadof two or three of such rows. Such a configuration further enhances theinterconnect capabilities of the semiconductor die carrier. FIG. 29(a)illustrates that, in all the embodiments of the present invention, thestabilizing section 1032 of each lead 103 may overlap or extend beyondthe inner surface of its corresponding side wall 102 b, if desired.Alternatively, in all of the embodiments of the present invention, astop such as that depicted in FIG. 10 could be used to preventover-insertion of the leads.

The semiconductor die carrier of FIG. 29(a) is manufactured in the samemanner that the die carriers shown in FIGS. 3 and 15 are manufactured.More particularly, for the embodiment of FIG. 29(a); the leads 103 areformed within the side walls 102 b via insertion or an insert moldingprocedure; the semiconductor die 101 is adhered to the floor 102 a; thebonding pads 104 of the die are connected to the bonding terminals 105of the leads 103, respectively; and the cavity of the carrier could befilled with high-temperature material such as VECTRA (trademark) and/ora cap could be sealed on top of the carrier. Exemplary dimensions forthe embodiment of FIG. 29(a) are a height of 3.4 mm; a width ofapproximately 28.0 mm; and a lead row length of 16.2 mm. In thisconfiguration, the semiconductor die carrier of FIG. 29(a) can bemanufactured to be approximately 57% smaller than conventional 304-pinQFPs.

FIG. 30 is a side view of the semiconductor die carrier of FIG. 29(a)prior to insertion of the leads 103 into the lead passages 107, and FIG.31 is a side view of the semiconductor die carrier of FIG. 29(a) afterinsertion of the leads 103. The patterns separated by dotted lines inFIGS. 30 and 31 may repeat along the length of each side wall 102 b.

As with previously-discussed embodiments, the arrangement of the leads103 within the side walls 102 b allows the bonding extension sections ofthe leads to be positioned to facilitate the connecting of the bondingterminals 105 of the leads to the bonding pads 104 on the semiconductordie 101. Also, as with previously-discussed embodiments, a four-rowembodiment in accordance with the present invention can be used forpackaging in connection with a semiconductor die 101 having two or morerows of bonding pads 104 arranged along each of its edges.Alternatively, the semiconductor die 101 could have a single row ofbonding pads 104 aligned along each of its edges.

FIG. 32 is a partial perspective view of the embodiment of FIG. 29(a)illustrating details of the manner in which the leads may interface witha PCB or other interface surface. FIG. 33(a) is a partial perspectiveview of a multiple-wall configuration in accordance with the embodimentof the semiconductor die carrier illustrated in FIG. 29(a). In themultiple-wall configuration, each of the side walls 102 b comprises aninner wall 102 b ₁ and an outer wall 102 b ₂, with a cavity separatingthe inner and outer walls. While not shown in FIG. 33(a), each side wall102 b in the multiple-wall configuration may comprise an inner wall, anouter wall, and one or more walls between the inner and outer walls. Themultiple-wall configuration eases insertion of the leads 103 into theside wall. After lead insertion, the cavity or cavities between theinner and outer walls may be filled with an epoxy or other adhesive,thereby retaining and stabilizing the leads, sealing the carrier, andpreventing contamination.

With regard to the multiple-wall configuration of FIG. 33(a), for eachlead 103, the inner lead passage 107 ₁ and outer lead passage 107 couldhave the same cross-sectional dimensions. Alternatively, for each lead103, the inner and outer lead passages 107 and 107 ₂, respectively,could have different cross-sectional dimensions. By using, for each lead103, an inner passage 107 ₁ that is narrower than the correspondingouter lead passage 107 ₂, for example, that lead will tend to beretained more securely within the semiconductor die carrier.

FIG. 33(b) is a perspective view of a lead 103 configured for use with amultiple-wall configuration such as that shown in FIG. 33(a). As seenfrom FIG. 33(b), the stabilizing section 1032 of each lead may includean unnotched portion 1032 a, a notched portion 1032 b, and an unnotchedportion 1032 c. When the semiconductor die carrier of the presentinvention is fully assembled, the unnotched portions 1032 a and 1032 cmay be disposed within the inner and outer walls of the multiple-wallconfiguration, respectively, and the notched portion may be positionedin a cavity between such walls. The notch in the stabilizing sectionprovides additional surface area for contact with the epoxy or otheradhesive filling the cavity between the inner and outer walls.

FIG. 33(c) is a perspective view of another lead 103 configured for usewith a multiple-wall configuration such as that shown in FIG. 33(a). Asseen from FIG. 33(c), the stabilizing section 1032 may include a raisedportion 1032 d which provides additional surface area for contact withthe epoxy or other adhesive filing the cavity between the inner andouter walls and, at the same time, which can act as a stop against aninner wall to prevent, for example, the over-insertion of the lead 103.

FIG. 33(d) is a partial perspective view illustrating the raised portion1032 d functioning as a stop when used in connection with an outer wall102 b ₂ allowing the raised portion to pass therethrough and an innerwall 102 b which does not allow the raised portion to pass therethrough.

FIG. 34 is a partial top view of an exemplary footprint which issuitable for use with the embodiment of FIG. 29(a). FIG. 35 is a partialtop view showing the manner in which the leads 103 extend from theexterior surface of the side walls 102 b for mounting on bonding pads109 of a PCB or other interface surface. The patterns separated bydotted lines in FIGS. 34 and 35 may repeat along the length of each sidewall 102 b.

As with previously-discussed embodiments, the arrangement of the leads103 with respect to the PCB or other interface surface facilitates therouting of traces on the PCB or other interface surface upon which, ifusing SMT technology, for example, or within which, if using PTHtechnology, for example, the semiconductor die carrier is being mounted.As seen from FIGS. 32-35, for example, the footprint of thesemiconductor die carrier of FIG. 29(a) is arranged into four rows. Thefirst row “a” of the footprint, closest to the side walls 102 b of thecarrier, is defined by the foot sections of the lower leads 103 a; thesecond row “b” of the footprint, further from the side walls 102 b ofthe carrier, is defined by the foot sections of the lower middle leads103 b; the third row “c” of the footprint, still further from the sidewalls 102 b of the carrier, is defined by the foot sections of the uppermiddle leads 103 c; and the fourth row “d” of the footprint, furthestfrom the side walls 102 b, is defined by the foot sections of the upperleads 103 d.

FIG. 36 is a partial view of the embodiment of the semiconductor diecarrier of FIG. 29(a) including additional components designated byreference numerals 116 and 117.

In FIG. 36, reference numeral 116 designates an insulating separatorformed of insulative material such as a thin sheet of polyester film orMYLAR (a trademark of E. I. DuPont de Nemours and Company), andreference numeral 117 designates a support column formed of, forexample, a liquid crystal polymer such as VECTRA (trademark). Theinsulating separator 116 and/or the support column 117 can be integrallymolded components of the substrate 102 or, alternatively, can beattached to the substrate 102 after molding of the substrate iscompleted. It should be noted that while FIG. 36 only shows one or twoleads from each of the four vertically spaced rows, in the configurationof FIG. 36, the leads 103 extend along essentially the entire length ofeach of the side walls 102 b of the semiconductor die carrier as inpreviously discussed embodiments. The insulating separator 116 alsoextends along essentially the entire length of each side wall 102 b.Also, while not shown in FIG. 36, several support columns 117 may beregularly or irregularly spaced along each of the side walls 102 b ofthe semiconductor die carrier to provide balanced support of theinsulating separator 116 along its length.

In the configuration of FIG. 36, the support columns 117 arranged atregular or irregular intervals along each side wall 102 b of thesemiconductor die carrier provide support for the insulating separator116 for that side wall. The insulating separator 116, in turn, providessupport for the bonding wires 106, and prevents shorting of the bondingwires by providing insulation between the multiple rows of leads. Such aconfiguration facilitates the attachment of bonding wires betweencorresponding pairs of the bonding pads 104 on the die 101 and thebonding terminals 105 and, additionally, facilitates the use ofincreased numbers of bonding pads 104 per linear inch on thesemiconductor die. In this regard, the insulating separator 116 makes iteasier to more reliably connect bonding wires to a semiconductor diehaving two or more rows of bonding pads arranged along each of itsedges. However, it should be noted that the configuration of FIG. 36could also be used with a semiconductor die 101 having, for example, asingle row of bonding pads 104 arranged along each of its edges.

A partial side view of the configuration of FIG. 36 is shown in FIG. 37.FIG. 37 illustrates features of the semiconductor die carrier of thepresent invention including a die bond adhesive 111 for mounting the die101 on the floor 102 a; a cavity filler 112 used to fill the cavitydefined by the floor 102 a and side walls 102 b of the carrier duringthe encapsulation process; and a sealing cap 113 made of plastic orother thermally-conductive material such as metal or VECTRA (trademark),and capable of functioning as a heat sink, for providing a cover for thesemiconductor die carrier.

The previously-discussed embodiments and configurations in accordancewith the present invention contemplate a prefabricated semiconductor diecarrier having one row of multiple leads or two, three, or fourvertically spaced rows of multiple leads. While not shown in theaccompanying drawings, in accordance with the present invention,prefabricated semiconductor die carriers having five or more verticallyspaced rows of multiple leads are also contemplated. Such prefabricatedsemiconductor die carriers are considered to be within the spirit andscope of the present invention.

FIG. 38 is a partial side view illustrating an aspect of the presentinvention that is applicable to all of the previously-discussedembodiments. FIG. 38 shows that a multi-layer ceramic component 118 withsteps formed along its sides, one step for each row of the leads 103,may be used to achieve electrical interconnection between the leads andthe bonding wires 106. The multi-layer ceramic component 118 has aplurality of levels of electrically conductive material and pads alongthe steps therein to allow for the transmission of signals between theleads 103 and the bonding wires 106 connected to the die 101. Connectionbetween the leads 103 and the ceramic component 118 may be achieved bysoldering, for example. The configuration of FIG. 38 has been found tobe particularly useful with smaller dies having larger I/O requirements.The use of ceramic components is also applicable to multi-die modules,discussed below, and to configurations incorporating bondingtechnologies such as C4 and TAB, for example. In particular, the use ofa stepped ceramic component such as that depicted in FIG. 18 facilitiesthe incorporation of C4 and TAB bonds within the various embodiments ofthe present invention.

FIG. 39(a) is a partial side view illustrating another aspect of thepresent invention that is applicable to all of the previously-discussedembodiments. In FIG. 39(a), the foot portion 1033 d for each of leads103 a, 103 b, and 103 c, is SMT-compatible. However, such foot portionsare not coplanar. As can be seen from FIG. 39(a), the foot portion ofthe middle lead 103 b is lower than the foot portion of the lower lead103 a, and the foot portion of the upper lead 103 c is lower than thefoot portion of the middle lead 103 b. Such non-coplanarity renders thesemiconductor die carrier of the present invention suitable for use witha multi-layer substrate or PCB 119 having SMT-compatible surfaces orbonding pads 109 a, 109 b, and 109 c formed at various layers thereof(for example, formed on an upper layer 119 a, a middle layer 119 b, anda lower layer 119 c thereof). A copending U.S. patent application to S.Crane et al., entitled “APPARATUS HAVING INNER LAYERS SUPPORTINGSURFACE-MOUNT COMPONENTS,” filed on even date herewith, and expresslyincorporated herein by reference, discloses multi-layer substrate andPCBs suitable for use in connection with the present invention and, inparticular, the configuration of the present invention illustrated inFIG. 39(a). Such substrates are equipped with plated or unplated wells120 b and 120 c each providing a passage to the inner layer bondingpads. The wells may be filled with solder 121 b and 121 c to maintainelectrical contact between corresponding pairs of bonding pads and leadsand to provide mechanical stability.

FIG. 39(b) depicts structure similar to that shown in FIG. 39(a), exceptin FIG. 39(b) the lead 103 c is SMT-mounted to an outer layer of themulti-layer substrate rather than to an inner layer. In FIG. 39(b), theleads from different rows are aligned in a straight line with respect toone another rather than being staggered, such that the leadconfiguration along the sides of the carrier and on the multi-layersubstrate does not require any gaps for routing traces. This allows fora three-row lead configuration that is very high in density.

FIG. 40 is a partial perspective view illustrating yet another aspect ofthe present invention that is applicable to all of thepreviously-discussed embodiments. As seen from FIG. 40, each of the leadpassages 107 in one or more (e.g., all) of the side walls 102 b may bemolded to have a primarily rectangular configuration with roundedcorners (i.e., a “dog bone” configuration). The rounded corners serve torelieve some of the stresses which can result on the plastic of the sidewalls when the leads 103 (not shown in FIG. 40) are inserted.

FIG. 41 is a perspective view of another aspect of the present inventionthat is applicable to all of the previously-discussed embodiments. Ascan be seen from FIG. 41, a plurality (e.g., four) of semiconductor dies101 may be incorporated within a prefabricated semiconductor die carrierin accordance with the present invention, thus allowing an even moreefficient usage of materials and board space. In FIG. 41, a multi-layerceramic component 122, having a plurality of levels of electricallyconductive material therein, is glued or otherwise adhered to the floor102 a, and the plurality of semiconductor dies 101 are glued orotherwise adhered to the multi-layer ceramic component. The dies may ormay not be electrically connected to the multi-layer ceramic componentusing C4, wire bond, TAB, or other bonding technologies. In the casewhere C4, TAB, or like bonding is used, conductive lands on the bottomsurface of the dies are used to provide electrical interconnectionbetween the dies and the ceramic component 122. In the case where wirebonding is used, bonding wires (not shown) connected at one end to thebonding pads 104 and at the other end to the ceramic component 122 areused to provide electrical interconnection between the dies and theceramic component.

The leads 103 are either soldered to the ceramic component 122, orelectrically connected to the ceramic component using bonding wires (notshown). For the bonding pads 104 along the outwardly-facing edges ofeach semiconductor die 101, rather than transmitting the signals betweenthe leads 103 and the bonding pads 104 via the multi-layer ceramiccomponent 122, such signals may be transmitted directly between thebonding pads and leads via bonding wires (not shown) directly connectedto the leads 103 at one end and directly connected to the bonding pads104 at the other end.

While FIG. 41 shows the incorporation of four semiconductor dies withina single prefabricated semiconductor die carrier in accordance with thepresent invention, either more or less dies per semiconductor diecarrier are contemplated. As stated previously, the incorporation of aplurality of semiconductor dies within a single die carrier allows moreeffective usage of materials and board space.

FIG. 42 is a partial perspective view of yet another aspect of thepresent invention that is applicable to all of the previously-discussedembodiments. As seen from FIG. 42, some of the leads 103 may be orientedin an upward direction, while others of the leads may be oriented in adownward direction. The number of rows of upwardly-oriented anddownwardly-oriented leads may be the same, as depicted in FIG. 42, orthe number of upwardly-oriented leads may be greater than or less thanthe number of downwardly-oriented leads. The configuration of FIG. 42allows the mounting of the leads to one or more substrates located abovethe semiconductor die carrier and also to one or more PCBs located belowthe semiconductor die carrier and, therefore, is particularly useful forthe purpose of creating stacks of PCBs or other substrates.

FIG. 43 is a partial perspective view of still another aspect of thepresent invention that is applicable to all of the previously-discussedembodiments. In FIG. 43, in addition to having leads 103 extendingsideways in a horizontal direction from its side walls 102 b, theprefabricated semiconductor carrier may also have leads 123 extendingdownward in a vertical direction from its floor 102 a. Thisconfiguration allows for more leads on a single semiconductor diecarrier and provides increased design flexibility and versatility. Thetop portions of the leads 123 may have plated (gold-plated, for example)tips 124 to facilitate bonding with the bonding wires 106.

In accordance with the configuration of FIG. 43, thedownwardly-extending leads 123 may be positioned around the periphery ofthe semiconductor die area. Additionally, or alternatively, thedownwardly-extending leads 123 may extend from the portions of the floor102 a directly beneath the semiconductor die area. This could beaccomplished, for example, by interposing a multi-layer ceramiccomponent (not shown) between each semiconductor die 101 and the floor102 a. Each semiconductor die 101 could be electrically connected to theinterposed multi-layer ceramic component by wire bonding, tape automatedbonding (TAB), or controlled collapse die connection (C4) interconnects,or the like, and the interposed multi-layer ceramic component could beelectrically connected to the leads 123 using ball grid array (BGA)technology. The use of downwardly-extending leads 123 could also beaccomplished without using an interposed multi-layer ceramic component.In this regard, each semiconductor die 101 could be directlyelectrically connected to the tip portions 124 of thedownwardly-extending leads 123 using C4 interconnect technology, forexample.

FIG. 44 is a partial bottom view showing a nested arrangement for thedownwardly-extending leads 123, with the leads being arranged into aplurality of groups 125. In the nested arrangement of FIG. 44, thegroups 125 are arranged in rows and columns on the floor 102 a (thedotted lines in FIG. 44 designate a row and a column, respectively); theelectrical Interconnect components of adjacent rows of the arrangementare staggered as are the groups from adjacent columns of thearrangement; and the groups are interleaved among one another in anested configuration such that a portion of each group of contactsoverlaps into an adjacent row of the groups of contacts or an adjacentcolumn of the groups of contacts. For the arrangement of FIG. 44, acenter-line to center-line distance X between columns of groups may be0.9 mm; a center-line to center-line distance Y between rows of groupsof contacts may be 1.25 mm; and the overall density of the arrangementmay be 1,028 contacts per square inch.

The nested configuration in FIG. 44 can be modified to provide evengreater densities. An example of one contemplated modification isdepicted in FIG. 45. In the arrangement of FIG. 45, the groups ofcontacts 125 are arranged in rows and columns on the floor surface 102a; and at least lead 123 of each group 125 includes a front surface 126facing outwardly and away from that group along a line initiallyintersected by a side surface 127 of a lead from another group ofcontacts. Also, in the arrangement of FIG. 45, adjacent groups ofcontacts are offset such that a line drawn from the center of a groupthrough the center of a contact for that group does not intersect thecenter of any of the groups directly adjacent that group. Moreover, inthe arrangement of FIG. 45, the distance d between like surfaces of theleads 123 may be 1.5 mm; and the overall density for the arrangement maybe 1,156 contacts per square inch.

The arrangements of FIGS. 44 and 45 may be modified to include a space128 at a center portion thereof to allow the use of wire bonding, TAB,and the like. FIGS. 46 and 47(a), respectively, are examples of themanner in which the arrangements of FIGS. 44 and 45 can be modified toinclude a space 128.

It should be noted that while the arrangements of FIGS. 44-47(a) usecross-shaped groups of contacts 125, other shapes are contemplated. Anarray of groups of contacts 125 each having an H-shaped space betweenits contacts may be used, for example, as seen from FIG. 47(b). Thearray of FIG. 47(b) may provide a density of 636 contacts per squareinch, for example.

Reference is made at this time to corresponding U.S. patent applicationSer. No. 07/983,083 to Stanford W. Crane, Jr., filed on Dec. 1, 1992,entitled “HIGH-DENSITY ELECTRICAL INTERCONNECT SYSTEM”; correspondingU.S. patent application to Stanford W. Crane, Jr., filed on even dateherewith, entitled “HIGH-DENSITY ELECTRICAL INTERCONNECT SYSTEM”; andcorresponding U.S. patent application to Stanford W. Crane, Jr., et al.,filed on even date herewith, entitled “SEMICONDUCTOR CHIP CARRIERAFFORDING A HIGH-DENSITY EXTERNAL INTERFACE.” These applicationsdisclose arrangements and other aspects relating to the groups ofdownwardly-extending contacts used by the present invention, and suchapplications are expressly incorporated herein by reference.

FIG. 48 includes two flowcharts. The flowchart at the left illustratessteps performed in the manufacturing of a conventional molded plasticsemiconductor package. The flowchart at the right illustrates stepsperformed in a manufacturing process for producing a prefabricatedsemiconductor carrier in accordance with the present invention. As canbe seen from FIG. 48, the present invention entails fewer stepsfollowing the die bond procedure as compared to conventionalmanufacturing processes.

In accordance with the present invention as depicted in the rightwardflowchart of FIG. 48, in a step S1, the substrate 102, including thefloor 102 a and side walls 102 b and, if desired, lead passages 107 andledges 108, are integrally formed using a molding process. As analternative to forming the lead passages 107 and ledges 108 during themolding process, the lead passages and/or ledges could be added aftermolding by, for example, removing material of the substrate to form thepassages and/or by applying insulative material (using an adhesive orepoxy, for example) to form the ledges. Components such as raisedplatform 115, insulating separator 116, and/or support columns 117 couldalso be formed either integrally during the molding process, or suchelements could be added after molding. Moreover, as seen from FIG. 7, itis envisioned that rather than being formed integrally in a singlemolding process, the floor 102 a and side walls 102 b could be moldedseparately, and then fastened together using an epoxy or other adhesive.The use of VECTRA (trademark) as the material for the substrate allowsthe parts of the semiconductor die carrier to be molded and assembledwith a high degree of accuracy. As an alternative to forming thesubstrate 102 and then inserting the leads into the substrate, thesubstrate could be formed around the leads in an insert molding process.

In a step S2, the leads 103 are formed. The lead formation step S2entails punching or stamping out individual leads from strips or drawnwire using, for example, a die. Applicants have found that byindividually manufacturing each lead 103, rather than using a lead frameto manufacture such leads, manufacturing costs are reduced and, at thesame time, yield is increased.

The aforementioned lead-manufacturing methods allow for selectiveplating and automated insertion. The leads for stamping can either beloose, on a bandolier carrier 129 (see, for example, FIG. 49), or on astrip since the asymmetrical shape lends itself to consistentorientation in automated assembly equipment. The different lengthexternal lead sections assist with orientation and vibratory bowlfeeding during automated assembly. The present invention is compatiblewith both stitching and gang-insertion assembly equipment. Theinsulative components have been designed to facilitate automatic androbotic insertion onto PCBs or in termination of wire to connector.

FIGS. 49(a) and 49(b), collectively referred to herein as “FIG. 49,”show the placement of the leads 103 on a bandolier or other fixture 129during formation of the semiconductor die carrier. The leads may bestamped in an L-shaped version as depicted, or stamped in a straightversion and then bent to achieve the L-shaped configuration. In otherwords, the use of a bandolier, in accordance with the present invention,is applicable to the formation of both straight and L-shaped versions ofthe leads 103.

Step S3 of FIG. 48 involves inserting the leads 103 into the side walls102 b of the substrate 102. In the situation where the floor 102 a andthe side walls 102 b are formed separately and then fastened together ata later time, the leads may be inserted into the side walls before theyare fastened to one another or to the floor. Each of the leads 103 isinserted into a corresponding one of the lead passages 107 in the sidewalls 102 b. The dimensions of the leads 103 and lead passages 107 aresuch that each lead fits tightly within it corresponding lead passage107. However, if desired, each lead 103 can be further fastened withinits corresponding lead passage 107 and/or onto a corresponding ledge 108using an epoxy or other adhesive material.

It should be kept in mind that rather than forming the substrate andthen inserting the leads into the side walls of the substrate, placementof the leads 103 with the side walls 102 b of the substrate may beaccomplished using an insert molding process. Insert molding isapplicable to all embodiments of the present invention.

In step S4, mechanical testing is performed to ensure that the leads 103are securely fastened within the substrate 102; to ensure thatcoplanarity of the leads 103 falls within an acceptable range; to ensurethat each lead is aligned properly within its respective lead passage;and the like. Also, electrical testing is performed to ensure thatsignals can be transmitted properly through the leads of the carrier tothe exterior of the carrier, and vice versa; and to ensure that none ofthe leads are shorted or would be likely to short during subsequentstages of the manufacture and usage of the semiconductor die carrier.

In accordance with step S5, the substrate 102 having leads 103 disposedtherein is packaged and then shipped to the place where a semiconductordie, manufactured in step S6, will be bonded to the substrate.Preferably, transportation packaging such as that illustrated in FIGS.50-55 is used to accomplish shipping. The packaging illustrated in FIGS.50-55 can be used to transport the semiconductor die carrier to thelocation at which die bonding will occur, and from that location to thecustomer following the die bonding.

A first type of transportation packaging is shown in FIG. 50. The typeof packaging shown in FIG. 50 will be referred to herein as a carriertray. The carrier tray includes an upper section 130 and a lower section131. Each of these sections comprises a base 132 upon which are formedone or more (e.g., twenty) support platforms 133 each having a set ofcorresponding support segments 134 associated therewith.

FIGS. 51-53 are views showing a semiconductor die carrier positionedwithin a carrier tray such as that depicted in FIG. 50. Thesemiconductor die carrier of FIGS. 51 and 52 has leads 103 which pointdownward, while the leads from the semiconductor die carrier in FIG. 53point upward.

As seen from FIGS. 51-53, the support platform 133 performs the functionof ensuring that the leads 103 of the semiconductor die carrier do nottouch the base 132. Such prevention reduces the occurrences of breakageand other potential complications.

The support segments of the upper section 130 are positioned slightlycloser to one another than are the support segments of the lower section131, or vice-versa, so that the upper and lower sections may be mated orplugged together prior to shipping for protection of the semiconductordie carrier. As seen from FIGS. 51-53, the lower section 131 of the diecarrier tray may hold the semiconductor die carrier with a main surfaceof the die carrier facing upward, so that when the upper section 130 isremoved at a destination location, such as the die assembly location,the die carrier can be removed (via suction, for example) to allow dieassembly, automatic mating or plugging, and the like. It should be notedthat the carrier tray is stable to an extent that die assembly or otherprocesses could be performed on the semiconductor die carrier while itis residing in the carrier tray. This would eliminate the steps ofremoving and returning the semiconductor die carrier to the carrier trayduring the manufacturing process.

A second type of transportation packaging is shown in FIG. 54(a). Thetype of packaging shown in FIG. 54(a) is a plastic tube or sleeve 135 ahaving an open end and a closed end. In using this type of packaging, aplurality of semiconductor die carriers are inserted through the openend in the plastic tube 135 a in sequential fashion. The firstsemiconductor die carrier to be inserted rests against the closed end ofthe plastic tube 135 a or a stop located adjacent the closed end, thesecond semiconductor die carrier to be inserted rests against the first,and so on. Each semiconductor die carrier may have a bar separator 135 bmolded or otherwise formed thereon. The bar separator keeps the leadsfrom adjacent semiconductor die carriers from tangling or contactingeach other when the carriers are packaged in the tube. When it isdesired to remove the semiconductor die carriers to accomplish dieassembly or the like, the die carriers are removed from the plastic tubein an order that is reversed with respect to the order of insertion intothe plastic tube.

FIG. 54(b) shows a completed semiconductor die carrier having four barseparators 135 b formed thereon. As an alternative to providing eachsemiconductor die carrier with four bar separators, each carrier may beprovided with two bar separators (for example, two bar separatorslocated on the same side wall of the carrier or two bar separatorslocated on opposing side walls of the die carrier at opposing corners,such as the uppermost and lowermost bar separators illustrated in FIG.54(b)) or some other number of bar separators.

A third type of transportation packaging is shown in FIG. 55. The typeof packaging shown in FIG. 55 will be referred to herein astape-and-reel packaging for a pick-and-place machine. In accordance withthis type of packaging, a conductive plastic tape 136 has a plurality ofsprockets 137 and a plurality of cavities 138 formed therein. Eachcavity may include a support platform 139 to isolate the leads of eachsemiconductor die carrier from the bottom of the cavity. In use, asemiconductor die carrier is placed in each cavity 138 and then a tapestructure (e.g., masking or cellophane tape) is adhered to theconductive tape 136 to hold the semiconductor die carriers within thecavities during shipping. The conductive tape 126 is then wound around areel or other magazine for holding tape and then transported. At thetransportation destination, a pick-and-place machine automatically feedsthe reel using sprockets 137, peels off the tape structure, and removesthe die carriers for die assembly, mounting, or the like, using asuction procedure. As with the first and second types of packagingdiscussed above, the third type of packaging is reusable so that thesame package can be used to transport the semiconductor die carrier tothe location at which die bonding will occur, and from that location tothe customer following die bonding.

Step S7 of FIG. 48 involves attaching the semiconductor die 101 to floor102 a or another support surface (for example, a raised platform 115)within the semiconductor die carrier. The attachment may be carried outusing an adhesive, an epoxy or the like.

Step S8 entails a bonding procedure wherein a bonding wire 106 isconnected between components of a pair including a bonding pad 104 onthe die 101 and a bonding terminal 105 on one of the leads 103. Thebonding wires allow electrical connection between the die 101 and thevarious leads 103.

In step S9, further electrical tests may be performed to provideadditional assurance that an acceptable product is being manufactured.In step S10, encapsulation is performed by filling the cavity defined bythe floor 102 a and the side walls 102 b of the substrate 102 withepoxy, a liquid crystal polymer such as VECTRA (trademark), or otherhigh-temperature material. Then the semiconductor die carrier may cappedwith a plastic component or thermally-conductive cap that may serve as aheat sink, and thereafter sealed, although use of a cap is optional. Itshould be noted that when a cap is used, the aforementionedencapsulation step becomes optional. The heat sink and/orhigh-temperature material which may be used for encapsulation andsealing facilitate the heat dissipation capabilities of thesemiconductor die carrier. In step S11, further mechanical andelectrical quality control testing may be performed to increase thelikelihood that the semiconductor die carrier will function as expected.

In accordance with step S12, the completed semiconductor die carrier ispackaged and shipped to the customer. Preferably, the semiconductor diecarrier is packaged and shipped to the customer using the sametransportation package it was received in. As indicated previously, thetransportation packaging illustrated in FIGS. 50-55 is particularlywell-suited for performing this type of double-transport function.

Step S13 relates to the mounting of the finished semiconductor diecarrier on or within an interface surface such as a PCB surface. In stepS13, either PTH technology or SMT methodology may be used to accomplishPCB interfacing or, alternatively, the carrier may be plugged into apluggable socket mounted on a PCB or other interface device.

FIG. 56 shows a lead 103 particularly well-suited for plugging into apluggable socket. By using an external lead section 1033 having anexpanded width, additional mechanical strength is provided. Suchmechanical strength facilitates plugging of the semiconductor diecarrier into a pluggable socket.

FIG. 57 shows a semiconductor die carrier in accordance with the presentinvention plugged into a pluggable socket. A pluggable socket inaccordance with the present invention includes an insulative substrate140 and a plurality of electrically conductive beams 141.

Each of the conductive beams 141 contacts a corresponding lead 103 fromthe semiconductor die carrier at one end, and at the other end, isattached to a PCB or other interface surface. The beams 141 may beattached to the interface surface by using the SMT method, as shown inFIG. 57, or by using PTH technology. The footprint pattern of theconductive beams 141 on the interface surface may be identical to any ofthe lead footprints discussed above and, as shown in FIG. 57, forexample, preferably matches the footprint corresponding to the leads ofthe semiconductor die carrier with which the socket is mating. Suchmatching between the footprint of the leads 103 and the footprint of thebeams 141 simplifies routing and trace design by allowing the sameconductive PCB pattern to accommodate both pluggable and SMT-compatibledie carriers.

The portions of the beams 141 extending above the substrate 140 (alsoshown in FIGS. 58 and 59) each apply a force to a corresponding one ofthe leads 103 in a direction away from the interior of the semiconductordie carrier (i.e., to the left in the illustration of FIG. 57). Thisforce is sufficient to hold the semiconductor die carrier in closeproximity to the socket and, at the same time, allows selectableplugging and unplugging of the semiconductor die carrier. The portionsof the beams 141 extending above the substrate 140 are flexible andspringy such that, prior to mating with leads from a semiconductor diecarrier, the leads bend in the direction away from the interior of thesemiconductor die carrier (to the left in the illustration of FIG. 57),and after mating, are upright as depicted in FIG. 57.

FIGS. 58 and 59 are similar to FIG. 57 in that they represent partialperspective views of a semiconductor die carrier in accordance with thepresent invention mounted within a socket that is attached to a PCB orother interface device using the SMT methodology. However, the forceapplied by the beams 141 against the leads 103 in FIGS. 58 and 59 is ina direction that is perpendicular with respect to the lengths of theleads. This force, like the force associated with the socket of FIG. 57,is sufficient to hold the semiconductor die carrier in close proximityto the socket and, at the same time, allows plugging and unplugging ofthe semiconductor die carrier. For the socket of FIGS. 58 and 59, theportions of the beams 141 extending above the substrate 140 are flexibleand springy such that, prior to mating with leads from a semiconductordie carrier, the leads bend in a direction perpendicular with respect tothe lengths of the leads, and after mating, are upright as depicted inFIGS. 58 and 59.

The configurations of the footprints of the semiconductor die carrier(or of the pluggable socket, if one is used) facilitate the routing oftraces on the PCB or other interface surface onto or within which thesemiconductor die carrier is being mounted. Further mechanical andelectrical testing can be performed after the mounting process iscompleted.

As compared to conventional methods, there are significantly fewerproduction steps involved in producing a semiconductor die carrier inaccordance with the present invention. The semiconductor die carrier ofthe present invention begins as a pre-formed platform into which the dieis inserted. Encapsulation is then accomplished by capping and sealingthe platform after it has been tested. This results in the eliminationof the entire molding, bending, and clean-up processes and the relatedbonding of the carrier. Because the leads of the present invention arepre-formed and inserted into the plastic platform, they are undisturbedby additional procedures conventionally performed after the die isintroduced into the semiconductor package. In the conventional process,the most sensitive aspects of the manufacturing process, encapsulatingthe die and electroplating and forming the leads, are performed afterthe die and the semiconductor package have been mated. This results incomparatively costly scrap, which may be due to lack of coplanarityamong the leads, breakage, wire bond failure due to high-pressuremolding, or other problems. All of these problems result in sacrificingthe die as well as the package. The semiconductor die carrier of thepresent invention, however, could be delivered to the die attach areacompletely tested for plating, mechanical integrity, and dimensionalcharacteristics, and the die need only be inserted into packages meetingacceptable quality standards. The elimination of the intermediateprocesses also reduces labor costs.

The semiconductor die carrier of the present invention can be configuredwith a precise number of leads easier than current designs due to theprogrammable nature of its assembly. A designer can specify variednumbers of leads or changes in package size, without the need to designand manufacture new lead frame configurations. With the presentinvention, both the number of leads on a side of a package, and thenumber of rows of leads, can be varied simply by producing a new moldfor the prefabricated platform and reprogramming the lead insertionequipment to vary the number of leads or lead configuration.

FIGS. 60-65 illustrate additional aspects relating to the semiconductordie carrier of the present invention.

FIG. 60, for example, shows that the leads 103 may extend straight outfrom one or more of the side walls of the semiconductor die carrierwithout bending or turning in a vertical or downward direction. Suchstraight leads are compatible for plugging within a socket or,alternatively, can function as Butt Joint Leads for SMT-mounting to asubstrate such as a PCB. For use with the structure of FIG. 60, forexample, the PCB or other such substrate to which the leads ofsemiconductor die carrier are SMT-mounted would be perpendicular withrespect to the floor of the carrier.

FIG. 61 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention having an alternate footconfiguration. In FIG. 61, the feet of the leads 103 are oriented suchthat the feet in the lower row 103 a point toward the semiconductor diecarrier and the feet in the upper row 103 b point away from the carrier.This type of configuration reduces the total surface area taken up onthe substrate (for example, a PCB) to which the semiconductor diecarrier is mounted. The concept of foot portions alternately facingtoward and away from the semiconductor die carrier is applicable to allof the embodiments of the present invention utilizing two or more rowsof leads.

FIG. 62 is a top view of a single-tier embodiment of a semiconductor diecarrier in accordance with the present invention. As with the multi-tierembodiments of the present invention, the single-tier embodiment of FIG.62 is formed using individually manufactured leads instead of leads froma lead frame.

FIG. 63 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention with the leads of at least one row(e.g., leads 103 b of the middle row) alternating with vias 142extending into the substrate to which the semiconductor die carrier ismounted. In other words, every lead 103 b in the middle row of theconfiguration has a via located on either side of it. Each via may berouted to one or more of the adjacent leads from its row and/or fromother ones of the rows of leads. Rather than being staggered, the leads(and also the vias) in FIG. 63 are aligned in a straight line withrespect to one another. The arrangement of FIG. 63 increases the numberof leads that can be located along the side of the semiconductor diecarrier.

FIG. 64 is a partial perspective view of a semiconductor die carrier inaccordance with the present invention showing an arrangement of bondingextensions within the carrier. In particular, in accordance with thestructure of FIG. 64, the bonding extensions of one or more of the leadsfrom an upper or middle row may extend into the semiconductor diecarrier to the same extent as bonding extension sections from lower onesof the rows of leads. In this case, the bonding extensions adjacent toone another but on different rows have the same length, bringing theirrespective bonding areas to the same plane. This arrangement facilitateswire bonding by reducing the length of the wire bond for second andhigher tiers of leads.

FIG. 65 illustrates that the leads 103 for use in connection with thesemiconductor die carrier of the present invention may have a roundedcross-section. The rounded lead 103 of FIG. 65 may include a flattenedportion 105 which may be plated with gold or other conductive materialand which may function as a bonding pad to allow attachment of the leadto a bonding wire. The other end of the rounded lead 103 has anailhead-type Butt Joint configuration resulting in a foot 1033 d whichtakes up less area.

FIG. 66 illustrates that the lead passages 107 in accordance with thepresent invention may be round. The round lead passages of FIG. 66 arenot only applicable for use with round leads, but also are applicablefor receiving square, rectangular, or other shapes of leads to establisha pressure fit relationship between the leads and lead passages.

As discussed above, the present invention provides many advantages overconventional packaging technology. Such advantages include the provisionof a semiconductor die carrier occupying reduced amounts of area andcapable of meeting the needs of existing and contemplated semiconductorand computer technology. FIG. 67 is a chart showing the surface areataken up by embodiments of the present invention versus current QFPtechnologies. The advantages provided by the present invention overconventional packaging technology illustrate that the present invention,unlike conventional packaging technology, is capable of keeping pacewith the rapid advances that are currently taking place in thesemiconductor and computer technologies.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the disclosed process andproduct without departing from the scope or spirit of the invention.Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A semiconductor die carrier comprising: a housingfor holding at least one semiconductor die and including: an end surfacehaving a perimeter; a peripheral side wall connected to the end surface,extending about the perimeter of the end surface and including an outerperipheral surface and an inner peripheral surface; and an inner wallwithin the perimeter of the end surface and including an outer surfacespaced from and opposing the inner peripheral surface of the peripheralside wall, and an inner surface facing the center of the housing; and aplurality of conductive leads inserted through the peripheral side walland the inner wall.
 2. The semiconductor die carrier according to claim1, further comprising a cavity extending between the inner peripheralsurface of the peripheral side wall and the outer surface of the innerwall.
 3. The semiconductor die carrier according to claim 2, furthercomprising a filler in the cavity to seal an interior of said housing.4. The semiconductor die carrier according to claim 3, furthercomprising a semiconductor die received on the end surface; and theinner wall encircles the semiconductor die.
 5. The semiconductor diecarrier according to claim 1, wherein the leads are arranged in multiplespaced apart rows.
 6. The semiconductor die carrier according to claim1, wherein the plurality of leads each comprise a substantially L-shape.7. The semiconductor die carrier according to claim 1, wherein theperipheral side wall comprises a first material and the end surfacecomprises a second material different from the first material.
 8. Asemiconductor die carrier comprising: a housing for holding at least onesemiconductor die and including: an end surface having a perimeter; aperipheral side wall connected to the end surface, extending about theperimeter of the end surface and including an outer peripheral surfaceand an inner peripheral surface; and an inner wall within the perimeterof the end surface and including an outer surface spaced from andopposing the inner peripheral surface of the peripheral side wall, andan inner surface facing the center of the housing; a plurality ofconductive leads inserted through the peripheral side wall and the innerwall; a cavity extending between the inner peripheral surface of theperipheral side wall and the outer surface of the inner wall; and afiller in the cavity to seal an interior of said housing, wherein thefiller comprises an adhesive.
 9. A semiconductor die carrier comprising:a housing for holding at least one semiconductor die and including: anend surface having perimeter; a peripheral side wall connected to theend surface, extending about the perimeter of the end surface andincluding an outer peripheral surface and an inner peripheral surface;an inner wall within the perimeter of the end surface and including anouter surface spaced from and opposing the inner peripheral surface ofthe peripheral side wall, and an inner surface facing the center of thehousing; and a plurality of spaced-apart ledges extending from the innersurface of the inner wall; a plurality of conductive leads insertedthrough the peripheral side wall and the inner wall; a cavity extendingbetween the inner peripheral surface of the peripheral side wall and theouter surface of the inner wall; a filler in the cavity to seal aninterior of said housing; and a semiconductor die received on the endsurface and encircled by the inner wall.